What is a 1/4 in. TRS jack....is it just a regular 1/4 inch cable....the PCI card i am looking at has 1/4 in. TRS inputs and im not sure if that is the same as say, a normal guitar cable
TRS stands for Tip, Ring, Sleeve - that is, it has three wires inside and not two. It is used for balanced connections (where the third wire sends a return signal to eliminate hum from electrical interference) and also for stereo signals into a stereo jack plug.
Your standard instrument cable will work fine, but it won't be balanced which for short runs usually doesn't matter (but you can't plug a guitar into the soundcard directly anyway, of course ).